How big until COVID?

It’s August 2022. There’s still a global pandemic, but COVID rates are finally plummeting! The latest data in San Francisco says that the asymptomatic positivity rate is only 2%. Let’s assume that means that if you picked a random person who is not showing any signs of being sick, there is a 2% chance that they have COVID.

You want to plan a party, but you don’t want COVID to be present at your party. How many (asymptomatic) people can you invite to your party while still having less than a 50% chance that anyone at your party has COVID?

Solution